// Base64工具
const Base64 = {
    // private property
    _keyStr: "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/="
    
    // public method for encoding
    , encode (input) {
      let output = "";
      let chr1; let chr2; let chr3; let enc1; let enc2; let enc3; let enc4;
      let i = 0;
    
      input = Base64._utf8_encode(input);
    
      while (i < input.length) {
        chr1 = input.charCodeAt(i++);
        chr2 = input.charCodeAt(i++);
        chr3 = input.charCodeAt(i++);
    
        enc1 = chr1 >> 2;
        enc2 = ((chr1 & 3) << 4) | (chr2 >> 4);
        enc3 = ((chr2 & 15) << 2) | (chr3 >> 6);
        enc4 = chr3 & 63;
    
        if (isNaN(chr2)) {
          enc3 = enc4 = 64;
        }
        else if (isNaN(chr3)) {
          enc4 = 64;
        }
    
        output = output +
          this._keyStr.charAt(enc1) + this._keyStr.charAt(enc2) +
          this._keyStr.charAt(enc3) + this._keyStr.charAt(enc4);
      } // Whend
    
      return output;
    } // End Function encode
    
    
    // public method for decoding
    , decode (input) {
      let output = "";
      let chr1; let chr2; let chr3;
      let enc1; let enc2; let enc3; let enc4;
      let i = 0;
    
      input = input.replace(/[^A-Za-z0-9\+\/\=]/g, "");
      while (i < input.length) {
        enc1 = this._keyStr.indexOf(input.charAt(i++));
        enc2 = this._keyStr.indexOf(input.charAt(i++));
        enc3 = this._keyStr.indexOf(input.charAt(i++));
        enc4 = this._keyStr.indexOf(input.charAt(i++));
    
        chr1 = (enc1 << 2) | (enc2 >> 4);
        chr2 = ((enc2 & 15) << 4) | (enc3 >> 2);
        chr3 = ((enc3 & 3) << 6) | enc4;
    
        output += String.fromCharCode(chr1);
    
        if (enc3 != 64) {
          output += String.fromCharCode(chr2);
        }
    
        if (enc4 != 64) {
          output += String.fromCharCode(chr3);
        }
    
      } // Whend
    
      output = Base64._utf8_decode(output);
    
      return output;
    } // End Function decode
    
    
    // private method for UTF-8 encoding
    , _utf8_encode (string) {
      let utftext = "";
      string = string.replace(/\r\n/g, "\n");
    
      for (let n = 0; n < string.length; n++) {
        const c = string.charCodeAt(n);
    
        if (c < 128) {
          utftext += String.fromCharCode(c);
        }
        else if ((c > 127) && (c < 2048)) {
          utftext += String.fromCharCode((c >> 6) | 192);
          utftext += String.fromCharCode((c & 63) | 128);
        }
        else {
          utftext += String.fromCharCode((c >> 12) | 224);
          utftext += String.fromCharCode(((c >> 6) & 63) | 128);
          utftext += String.fromCharCode((c & 63) | 128);
        }
    
      } // Next n
    
      return utftext;
    } // End Function _utf8_encode
    
    // private method for UTF-8 decoding
    , _utf8_decode (utftext) {
      let string = "";
      let i = 0;
      let c; let c1; let c2; let c3;
      c = c1 = c2 = 0;
    
      while (i < utftext.length) {
        c = utftext.charCodeAt(i);
    
        if (c < 128) {
          string += String.fromCharCode(c);
          i++;
        }
        else if ((c > 191) && (c < 224)) {
          c2 = utftext.charCodeAt(i + 1);
          string += String.fromCharCode(((c & 31) << 6) | (c2 & 63));
          i += 2;
        }
        else {
          c2 = utftext.charCodeAt(i + 1);
          c3 = utftext.charCodeAt(i + 2);
          string += String.fromCharCode(((c & 15) << 12) | ((c2 & 63) << 6) | (c3 & 63));
          i += 3;
        }
    
      } // Whend
    
      return string;
    } 
}
//生成随机 GUID 数
const guid = () => {
    function S4() {
        return (((1 + Math.random()) * 0x10000) | 0).toString(16).substring(1);
    }
    return (S4() + S4() + "-" + S4() + "-" + S4() + "-" + S4() + "-" + S4() + S4() + S4());
}


exports.Base64 = Base64
exports.guid = guid